As noted in U.S. Pat. No. 6,287,690, it is well known in the textile industry to produce fire resistant fabrics for use as upholstery, mattress ticking, panel fabric, etc., using yarn formed of natural or synthetic fibers, and then treating the fabric with fire retardant chemicals. Conventional fire retarding chemicals include halogen-based and/or phosphorous-based chemicals. Such treated fabrics reportedly are heavier than similar types of non-fire retardant fabrics, and are said to have a more limited wear life.
The incidence of mattress fires in the United States is such that there have been efforts to establish standards for testing open flame flammability of mattresses. California, e.g., has enacted regulations in 2001 which requires all mattresses to be sold effective January 2005 to meet the performance requirements of California Technical Bulletin 603, now replaced by 16 CFR 1633. This is a consequence, among other things, of the fact that the foam used in mattresses can be a source of fuel which can be ignited and quickly engulf the mattress in flames.
Not surprisingly, therefore, one can uncover numerous disclosures aimed at modifying the burning characteristics of fiber materials. For example, in U.S. Pat. No. 4,600,606 a method of flame retarding textile and related fibrous materials is reported, which relies upon the use of a water-insoluble, non-phosphorous containing brominated aromatic or cycloaliphatic compounds along with a metal oxide. U.S. Pat. No. 4,026,808 reports on the use of a phosphorous containing N-hydroxy-methyl amide and tetrakis(hydroxymethyl) phosphonium chloride. U.S. Pat. No. 3,955,032 confirms the use of chlorinated-cyclopentadieno compounds, chlorobrominated-cyclpentadieno compounds, either alone or in combination with metal oxides.
U.S. Pat. No. 4,702,861 describes a flame retardant composition for application as an aqueous working dispersion onto surfaces of combustible materials. Upon exposure to elevated temperatures and/or flame, the formulation reportedly creates a substantially continuous protective film generally encapsulating and/or enveloping the surface of the article onto which it is applied. The film-forming materials are based upon an aqueous latex dispersion of polyvinylchloride-acrylic copolymer together with certain other film-forming and viscosity controlling components.
Other disclosures which offer additional background information include U.S. Pat. No. 4,776,854 entitled “Method for Flameproofing Cellulosic Fibrous Materials”; U.S. Pat. No. 5,051,111 entitled “Fibrous Material”; U.S. Pat. No. 5,569,528 entitled “Treating Agent for Cellulosic Textile Material and Process for Treating Cellulosic Textile Material”; and U.S. Pat. No. 6,309,565 entitled “Formaldehyde-Free Flame Retardant Treatment for Cellulose-Containing Materials”.
It is also worth mentioning that within the various efforts to provide flame resistant fabric products, various polymers themselves have emerged as substrates for use as flame resistant fibers. For example, melamine and melamine/formaldehyde based resinous fibers are said to display desirable heat stability, solvent resistance, low flammability and high-wear characteristics. One form of melamine/formaldehyde fiber is marketed under the tradename Basofil™. In addition, the aromatic polyamide family or aramids reportedly have high strength, toughness, and thermal stability. Aramid fibers are marketed under the tradenames Nomex™ and Kevlar™.
Furthermore, acrylic fibers are well-known in the synthetic fiber and fabric industries, as are the modified acrylic fibers (modacrylic). Such modacrylics are relatively inexpensive, and have been used in various blends with the fibers noted above to provide fire-resistant fabric material. One particular modacrylic fiber is sold under the tradename Kanecaron™ Protex, which is available from Kaneka Corporation, Japan.
In addition, flame retardant viscose fibers have become available, and one particular viscose fiber is sold under the tradename Visil™. More specifically, Visil™ is said to comprise a silicic acid containing viscose, with a limiting oxygen index (i.e., the minimum concentration of oxygen necessary to support combustion) in the range of 27-35, depending upon a particular textile construction.
Finally, it is worth noting that various manufacturers have produced and sold fire-resistant fabric material. They are as follows: 1. E.R. Carpenter's “Fire Stop™” which relies upon Basofil™/modacrylic high loft batting; 2. Chiquola Industrial Fabric's “FireGuard™” which relies upon core spun flame retardant yarns into woven or knit form; 3. ChemTick Coated Fabrics “Flame Safe™” which relies upon core spun yarn in woven configuration with flame retardant treatment; 4. Elk Corporation's “VersaShield™” which relies upon a woven fiberglass base with a soft foam like coating on one side; 5. Jones Fiber Products, Inc.'s “T-Bond™” which relates to a flame retardant treatment of cotton batting; 6. Legett & Platt's “Pyro-Gon™” which is a batting of a blend of Pyron (panox) fibers with other fibers; 7. MLM, LLC's “Allesandra” which is a core spun flame retardant yarn in woven form; 8. Tex Tech's various blends of Basofil™ and Nomex™, Kevlar™ and PBI in the form of needlepunched felts; and 9. Ventex's “Integrity 30™”, SpunGold™ and AKTIV™ which collectively relate to various products of knits and nonwoven battings that may include Basofil™, Panox, Kevlar™ or Nomex™.
It is therefore an object of the present invention to expand upon the technology directed at the manufacture of flame retardant materials, and develop a fire resistant needle punched material that can serve, among other things, as a protective liner material. More specifically, it is an object of the present invention to develop new types of needle punched materials that rely upon a foundation component of a modified acrylic type fiber that is based upon a copolymer of polyacrylonitrile and a halogen based monomer to provide an inexpensive fire blocking composition.
It is also an object of the present invention to provide a fire-resistant material which relies upon a needle punched non-woven manufacture of two principal components, wherein one component is selected to provide non-burning characteristics, and a second component is selected to support and maintain the first component in place during burning as well as to provide non-burning characteristics, thereby resulting in a synergistic composition that reduces the burn rate in a given liner application.